Electrically conductive tapes have numerous constructions and have conventionally been formed using various methods. For example, in one construction, an electrically conductive adhesive tape can be formed by dispersing finely divided silver in a pressure sensitive adhesive and coating the adhesive on an electrically conductive backing. In another construction, a conductive tape is formed with a monolayer of large conductive particles on the pressure sensitive adhesive. In yet another embodiment, an electrically conductive backing is embossed to have a plurality of closely spaced electrically conductive projections that extend almost through the layer of adhesive. One characteristic common to all of these constructions is that they do not provide reliable electrical connections to very small size contacts.
There is an increasing demand for thinner conductive single-sided tapes which can provide reliable electrical connection to very small contacts. This is in part because connections to small contacts are becoming more important for many electronic uses of conductive tapes. One method of currently accomplishing this is to include a layer of adhesive made conductive by the inclusion of small, complex metal particles having a low apparent density for reliable electrical connections to very small contacts.
There has also been an increasing demand for thinner conductive single-sided tapes which can provide good workability and handling properties. This is generally because most foil tapes are easily curled when the release liner is removed from the adhesive. The curling may become an issue as the foil tapes become thinner.